Face shields to protect various medical personnel, particularly dentists or medical technicians and the like, from being contacted with infectious liquids are commonly worn.
Face shields presently in existence are of several types. One type hooks onto a pair of spectacles and is a face shield for the portion of the face from the eyebrows down. Such a shield is a continuous sheet of plastic without any openings and the wearer must look not only through the lenses of the spectacles, but also through the plastic sheet Another type of shield is one which attaches to a visor which is worn with a headband, and the shield may be lowered and raised much like a welder's mask.
U.S. Pat. No. 3,991,753 to Viesca discloses a face shield which is a continuous sheet of plastic without any openings in it which has attachment hooks to hook over the upper rim of a pair of spectacles. A wearer of this mask must look through both the lenses of the spectacles and the plastic material in the mask. This particular mask does not protect against liquid materials which may spray or splash over the top of the mask and drop into the eyes.
A visor-supported plastic shield for dentists is illustrated in U.S. Pat. No. 4,701,965 to Landis. Because of the curved surface of the shield, some optical distortion is very likely to occur. Another type of a mask is illustrated in U.S. Pat. No. 3,310,812 to Gaisser. This mask is a flexible sheet of plastic cut in a kidney configuration so that it may be bent about the face with a pair of elastic loops at either side looped over the ears and held in place. This mask does not protect the nose and mouth regions.
Another safety mask is illustrated in U.S. Pat. No. 3,298,031 to Morgan. This mask is a two-part mask in which a pair of goggles similar to ski goggles has a sheet of plastic hinged to the goggles so that the plastic may be pulled down to protect the nose and other facial regions. The plastic sheet has cut-out areas so that the only vision area is through the goggles. The goggles are held on the head by a strap, and there is sufficient room underneath the goggles to permit anyone needing corrective lenses to wear glasses or spectacles underneath the goggles. The plastic shield is pinned on either side of the goggles to form a hinge. The shield may be swung up and down to protect the lower part of the face.
Other face shields are illustrated in patents to Burstyn, U.S. Pat. No. 1,582,164; DuBois, U.S. Pat. No. 2,774,970; Atha, U.S. Pat. No. 2,978,709; and LaRoche, U.S. Pat. No. 1,279,884.
The LaRoche patent illustrates a gauze-type, partial-face mask depending from a pair of spectacles, while the face shield of Atha is a full-face shield having a "window area" in front of the eyes. The Atha shield depends from a carrier headband.
The DuBois shield is a continuous, flexible full-face plastic shield which detachably mounts on a pair of lugs projecting forward of the temples on a spectacle-like frame which holds the shield in place. Vision is through the flexible plastic shield and spectacle frames do not have means for holding lenses.
The Burstyn shield is mounted somewhat similarly to the Atha shield, i.e., to a pair of spectacle temples which are permanently fixed directly to the shield. The Burstyn shield is a partial-face shield which has its upper edge at about eye level of the wearer. A pair of crescent shaped cut-outs (recesses) are made in the upper edge of the shield. Semi-circular frames are permanently mounted to the shield so that lenses of glass may be removably fitted within the semi-circular frames. While the device provides vision through glass lenses, it has temples mounted to the shield and not to the glass lenses which are connected to a bridge and are removable from the shield. Also, the shield does not extend above the eyes. The manner of removing the lenses by pulling them upward from the semi-circular frame would preclude the shield from being simply extended upwardly. The pair of lenses are specially constructed with a lifting bar (bridge) formed in a bow-shape above and between the glass lenses so the lenses could be removed from the shield without removing the shield from the face of the user.